Hydraulic accumulator-based controllable pressure injection device and method

ABSTRACT

A hydraulic accumulator-based controllable pressure injection device includes a pressure storage system, a pressure maintaining system, a sealing system, and an injection system. The pressure storage system includes a pressure cylinder front half portion, an annular piston and a middle connecting body. The pressure maintaining system includes an accumulator, a pressure cylinder rear half portion and a rear end cover. The sealing system includes a hydraulic propulsion cylinder, a propulsion piston, a front end cover, a sealing tube, a thickened end portion, and an expansion rubber tube. The injection system includes a hydraulic valve body and an injection gun tube. The hydraulic accumulator-based controllable pressure injection device quickly applies pressure to the bottom of a borehole in a hydraulic manner, so that rock experiences tensile failure, and the hard rock excavation efficiency is improved.

CROSS REFERENCES TO THE RELATED APPLICATIONS

This application is the national phase entry of InternationalApplication No. PCT/CN2018/106902, filed on Sep. 21, 2018, which isbased upon and claims priority to Chinese Patent Application No.201810378319.6, filed on Apr. 25, 2018, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a device for cracking rock with highpressure liquid flow, and in particular, to a hydraulicaccumulator-based controllable pressure injection device and method,belonging to the technical field of mining roadway excavationengineering.

BACKGROUND

The 21st century is a period of great development of tunnels andunderground space. With the development of economy and the improvementof science and technology of China, there are more and more excavationmeans for the underground space, but with the increasing demand for theunderground space and the increase of excavation depth, the developmentand construction of the underground space are confronted with newdifficulties and challenges. As the most important energy source in theenergy system of China, the development and utilization of coal aredependent on the excavation of underground roadways and the excavationof deep rock masses. With the development of China's economicconstruction, the demand for coal has increased steadily, and theexcavation of underground deep hard rock has become a major technicaldifficulty to be solved, which seriously restricts the coordinateddevelopment of coal mine production.

At present, the domestic rock roadway excavation mainly adopts aborehole-blasting method and a fully-mechanized excavating method, butthe two excavation processes both have many problems such as low levelof footage and low degree of mechanization. Especially, in hard rockexcavation, the excavation efficiency is significantly reduced.

SUMMARY

In order to overcome the above-mentioned defects in the prior art, thepresent invention provides a hydraulic accumulator-based controllablepressure injection device and method, which can convert the pressure ofa high pressure fluid into a cracking force acting on the inside ofrock, thereby effectively improving the hard rock excavation efficiency.

The present invention adopts the following technical solutions to solvethe technical problem:

A hydraulic accumulator-based controllable pressure injection device,including a pressure storage system, a pressure maintaining system, asealing system, and an injection system. The pressure storage systemincludes a pressure cylinder front half portion, an annular piston and amiddle connecting body, which are mounted on the same axis, the annularpiston is located between a pressure cylinder and a hydraulic adjustingtube and dynamically sealed, the pressure cylinder front half portion isfixedly connected to an end portion of the middle connecting body, and ahigh pressure fluid inlet flow passage having both ends respectivelycommunicating with the outside and an inner chamber of the pressurecylinder front half portion is provided in the middle connecting body.The pressure maintaining system includes an accumulator, a pressurecylinder rear half portion and a rear end cover, the pressure cylinderrear half portion and a rear end of the hydraulic adjusting tube aredetachably connected to the rear end cover, respectively, and sealed, anouter end of the rear end cover is provided with the accumulator, andthe accumulator is communicated to an inner chamber of the pressurecylinder rear half portion. The sealing system includes a hydraulicpropulsion cylinder, a propulsion piston, a front end cover, a sealingtube, a thickened end portion, and an expansion rubber tube, the sealingtube sequentially penetrates through the axes of the front end cover andthe propulsion piston, a rear end of the sealing tube and the propulsionpiston are fixedly connected into a whole, the expansion rubber tube anda front end of the sealing tube are butted and coaxially connected, thesealing tube and the front end cover are dynamically sealed, thepropulsion piston and the hydraulic propulsion cylinder are dynamicallysealed, a front end of the hydraulic propulsion cylinder is detachablyconnected to a rear end of the front end cover and sealed, a rear end ofthe hydraulic propulsion cylinder is fixedly connected to the middleconnecting body, and an oil inlet and outlet port having both endsrespectively communicating with the outside and an inner chamber of thehydraulic propulsion cylinder is also provided in the middle connectingbody. The injection system includes a hydraulic valve body and aninjection gun tube, the hydraulic valve body is coaxially mounted insidea front port of the hydraulic adjusting tube in the pressure storagesystem and the two are dynamically sealed at front ends, the injectiongun tube is coaxially sleeved inside the sealing tube and penetratesthrough the propulsion piston, the thickened end portion is coaxiallyand detachably connected to a front end of the injection gun tube, arear end of the injection gun tube is fixedly connected to the middleconnecting body, and a front end of the hydraulic valve body has a conearea fitting a groove at a rear end of the injection gun tube.

A hydraulic accumulator-based controllable pressure injection method,including the following steps:

a, inserting an injection gun tube into a rock borehole, and pushing, bya propulsion piston, a sealing tube to push an expansion rubber tube toa thickened end portion such that an outer diameter of the injection guntube is enlarged to fit an inner wall of the rock borehole to form asealed space at the bottom of the rock borehole;

b, starting a hydraulic valve body to fit a groove at a rear end of theinjection gun tube, and feeding a high pressure fluid medium via a highpressure fluid inlet flow passage to form a high pressure area in afront section of a pressure cylinder;

c, monitoring pressure changes of the pressure cylinder and anaccumulator; and

d, after a pressure reaches a predetermined value, reducing the pressurein a hydraulic adjusting tube to 0 gradually, when a pressure generatedby the high pressure area against a cone area at a front end of thehydraulic valve body is greater than an oil path pressure in thehydraulic adjusting tube at a rear end, allowing the hydraulic valvebody to slide backwards to be separated from the groove at the rear endof the injection gun tube, and allowing the high pressure fluid mediumto instantaneously surge into the sealed space at the bottom of the rockborehole under own pressure and the thrust of an annular piston, wherethe pressure generated is sufficient to cause the rock to break from theinside.

Compared with the prior art, the hydraulic accumulator-basedcontrollable pressure injection device and method of the presentinvention can realize breaking of hard rock under a lower pressure withhigh rock-breaking efficiency, safety and environmental protection byutilizing the characteristic that the tensile strength of the rock isfar lower than the compressive strength. The device may replace aconventional borehole-blasting excavation mode, is easy to be combinedwith excavation equipment such as a heading machine and a rock drill,can realize underground exploitation and excavation by no one or fewpeople when connected to electromechanical control equipment, and hasthe advantages of small scale, easy control and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below with reference tothe accompanying drawings and the embodiments.

FIG. 1 is a structural schematic diagram according to one embodiment ofthe present invention.

FIG. 2 is an enlarged view of part A in FIG. 1.

FIG. 3 is an enlarged view of part B in FIG. 1.

In the figures, 1, rear end cover; 2, accumulator; 3, hydraulicadjusting tube; 4, pressure cylinder; 5, annular piston; 6, hydraulicvalve body; 6-1, cone area; 7, middle connecting body; 7-1, highpressure fluid inlet flow passage; 7-2, oil inlet and outlet port; 8,hydraulic propulsion cylinder; 9, propulsion piston; 10, front endcover; 11, injection gun tube; 11-1, groove; 12, sealing tube; 13,expansion rubber tube; 14, thickened end portion.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In order to make the purposes, technical solutions and advantages of theembodiments of the present invention clearer, the technical solutions inthe embodiments of the present invention will be clearly and completelydescribed below with reference to the accompanying drawings in theembodiments of the present invention. It is apparent that the describedembodiments are a part of the embodiments of the present invention, andnot all embodiments. All other embodiments obtained by a person ofordinary skill in the art based on the embodiments in the presentinvention without creative efforts fall within the scope of protectionof the present invention.

For the sake of clarity of description, it is specifically stated that a“front” end, a “front” half portion or a “front” side mentioned in thepresent embodiment refers to a downward direction in FIG. 1, and “rear”is in line with an “upward” direction.

In the embodiment shown in FIG. 1 to FIG. 3, a hydraulicaccumulator-based controllable pressure injection device for applying acracking force in a rock borehole to break rock from the inside of thehole includes a pressure storage system, a pressure maintaining system,a sealing system, and an injection system, where the pressure storagesystem includes a pressure cylinder front half portion 4-2, an annularpiston 5 and a middle connecting body 7, which are mounted on the sameaxis, the annular piston 5 is located between a pressure cylinder 4 anda hydraulic adjusting tube 3 and dynamically sealed, the pressurecylinder front half portion 4-2 is fixedly connected to an end portionof the middle connecting body 7, a high pressure fluid inlet flowpassage 7-1 having both ends respectively communicating with the outsideand an inner chamber of the pressure cylinder front half portion 4-2 isprovided in the middle connecting body 7, a high pressure fluid mediumenters the pressure cylinder 4 through the high pressure fluid inletflow passage 7-1, and the annular piston 5 is pushed to move backwardsto store the high pressure fluid medium; the pressure maintaining systemincludes an accumulator 2, a pressure cylinder rear half portion 4-1 anda rear end cover 1, the pressure cylinder rear half portion 4-1 and arear end of the hydraulic adjusting tube 3 are detachably connected tothe rear end cover 1, respectively, and sealed, an outer end of the rearend cover 1 is provided with the accumulator 2, and the accumulator 2 iscommunicated to an inner chamber of the pressure cylinder rear halfportion 4-1; the accumulator 2 absorbs high pressure oil from thepressure cylinder 4, when the high pressure fluid medium at a front endof the annular piston 5 is injected, the accumulator 2 releases storedhydraulic oil to maintain the pressure of the pressure cylinder 4 not todrop drastically within a short time; and as the pressure in thepressure cylinder 4 rises to a set pressure, an oil pressure in thehydraulic adjusting tube 3 is reduced, the hydraulic valve body 6 movesbackwards under the pressure of the high pressure fluid medium, and thehigh pressure fluid medium is injected from an injection gun tube 11.The sealing system includes a hydraulic propulsion cylinder 8, apropulsion piston 9, a front end cover 10, a sealing tube 12, athickened end portion 14, and an expansion rubber tube 13, the sealingtube 12 sequentially penetrates through the axes of the front end cover10 and the propulsion piston 9, a rear end of the sealing tube 12 andthe propulsion piston 9 are fixedly connected into a whole, theexpansion rubber tube 13 and a front end of the sealing tube 12 arebutted and coaxially connected, the sealing tube 12 and the front endcover 10 are dynamically sealed, the propulsion piston 9 and thehydraulic propulsion cylinder 8 are dynamically sealed, the expansionrubber tube 13 can move along the axis with the propulsion piston 9, afront end of the hydraulic propulsion cylinder 8 is detachably connectedto a rear end of the front end cover 10 and sealed, a rear end of thehydraulic propulsion cylinder 8 is fixedly connected to the middleconnecting body 7 by welding or the like, an oil inlet and outlet port7-2 having both ends respectively communicating with the outside and aninner chamber of the hydraulic propulsion cylinder 8 is also provided inthe middle connecting body 7, and a backward pressure from the highpressure fluid medium at the front end presses the hydraulic oil intothe accumulator through the annular piston 5 for storing the pressure inthe system. The injection system includes a hydraulic valve body 6 andan injection gun tube 11, the hydraulic valve body 6 is coaxiallymounted inside the hydraulic adjusting tube 3 in the pressure storagesystem and the two are dynamically sealed at front ends, and finally,the hydraulic valve body 6 can only be translated in a groove at thefront end of the hydraulic adjusting tube 3, and cannot be moved out;and the injection gun tube 11 is coaxially sleeved inside the sealingtube 12 and penetrates through the propulsion piston 9, the thickenedend portion 14 is coaxially and detachably connected to a front end ofthe injection gun tube 11, a rear end of the injection gun tube 11 isfixedly connected to the middle connecting body 7 by welding or thelike, and the front end of the hydraulic valve body 6 has a cone area6-1 fitting a groove 11-1 at a rear end of the injection gun tube 11.The hydraulic valve body 6 is used to open and close a communicationstate between the pressure cylinder 4 and the injection gun tube 11, andthe start and stop control of the injection system is realized by thehydraulic adjusting tube 3. Preferably, the cone area 6-1 at the frontend of the hydraulic valve body 6 fits the groove 11-1 at the rear endof the injection gun tube 11, but there is still a part of the cone areaexposed to a high pressure fluid, and a backward thrust is generated forthe hydraulic valve body 6. The annular piston 5 is dynamically sealedwith the pressure cylinder 4 and the hydraulic adjusting tube 3 througha guide strip and a Glyd ring, respectively, so that the annular piston5 is slidable between the hydraulic adjusting tube 3 and the pressurecylinder 4.

In the present embodiment, the pressure cylinder front half portion 4-2and the end portion of the middle connecting body 7 are welded together.The pressure cylinder rear half portion 4-1 and the rear end cover 1 areconnected by threads, and an O ring is provided therebetween forsealing. The hydraulic propulsion cylinder 8 is connected to the rearend of the front end cover 10 by threads, and an O ring is providedtherebetween to ensure sealing of hydraulic oil. A guide strip and astep seal are provided between the front end cover 10 and the sealingtube 12 to ensure sealing of the hydraulic oil. The thickened endportion 14 is connected to the injection gun tube 11 by threads, and thehydraulic valve body 6 and the hydraulic adjusting tube 3 aredynamically sealed through a guide sleeve and a Glyd ring, so that thehydraulic valve body 6 is pushed by hydraulic oil in the tube to moveforwards, and the cone area 6-1 at the front end of the hydraulic valvebody 6 fits the groove 11-1 at the rear end of the injection gun tube 11to form a sealed space in the pressure cylinder 4.

In order to buffer the annular piston 5, a raised circular ring isprovided on an end face of the middle connecting body 7 facing thepressure cylinder 4, the raised circular ring is located in an innerchamber of the pressure cylinder 4, and the height of the raisedcircular ring can be 1 cm.

Preferably, the groove 11-1 at the rear end of the injection gun tube 11and the cone area 6-1 at the front end of the hydraulic valve body 6 areboth chamfers of 45 degrees. Furthermore, the groove 11-1 is a 1×1 mmchamfer, and the cone area (6-1) is an 8×8 mm chamfer.

A hydraulic accumulator-based controllable pressure injection methodaccording to an embodiment of the present invention includes thefollowing steps:

a, inserting an injection gun tube 11 into a rock borehole, pushing, bya propulsion piston 9, a sealing tube 12 to push an expansion rubbertube 13 to a thickened end portion 14 such that an outer diameter of theinjection gun tube 11 is enlarged to fit an inner wall of the rockborehole to form a sealed space at the bottom of the rock borehole;

b, starting a hydraulic valve body 6 to fit a groove 11-1 at a rear endof the injection gun tube 11, and feeding a high pressure fluid mediumvia a high pressure fluid inlet flow passage 7-1 to form a high pressurearea in a front section of a pressure cylinder 4;

c, monitoring pressure changes of the pressure cylinder 4 and anaccumulator 2; and

d, after a pressure reaches a predetermined value, reducing the pressurein a hydraulic adjusting tube 3 to 0 gradually, when a pressuregenerated by the high pressure area against a cone area 6-1 at a frontend of the hydraulic valve body 6 is greater than an oil path pressurein the hydraulic adjusting tube 3 at a rear end, allowing the hydraulicvalve body 6 to slide backwards to be separated from the groove 11-1 atthe rear end of the injection gun tube, and allowing the high pressurefluid medium to instantaneously surge into the sealed space at thebottom of the rock borehole under own pressure and the thrust of anannular piston 5, where the pressure generated is sufficient to causethe rock to break from the inside.

The high pressure fluid medium may be high pressure foam or highpressure water.

The controllable pressure injection of the device is characterized inthat the hydraulic adjusting tube 3 is supplied with oil by acontrollable hydraulic pumping station, and the magnitude of a pressurefor injecting a fluid medium is controlled by setting different oilsupplies.

The above is only a preferred embodiment of the present invention, andis not intended to limit the present invention in any form. Any simplemodifications and equivalent changes made to the above embodiments inaccordance with the technical essence of the present invention fall intothe scope of protection of the present invention.

What is claimed is:
 1. A hydraulic accumulator-based controllablepressure injection device, comprising a pressure storage system, apressure maintaining system, a sealing system, and an injection system,wherein the pressure storage system comprises a pressure cylinder fronthalf portion, an annular piston and a middle connecting body, which aremounted on a same axis, the annular piston is located between a pressurecylinder and a hydraulic adjusting tube and dynamically sealed, thepressure cylinder front half portion is fixedly connected to an endportion of the middle connecting body, and a high pressure fluid inletflow passage having both ends respectively communicating with an outsideand an inner chamber of the pressure cylinder front half portion isprovided in the middle connecting body; the pressure maintaining systemcomprises an accumulator, a pressure cylinder rear half portion and arear end cover, the pressure cylinder rear half portion and a rear endof the hydraulic adjusting tube are detachably connected to the rear endcover, respectively, and sealed, an outer end of the rear end cover isprovided with the accumulator, and the accumulator is communicated to aninner chamber of the pressure cylinder rear half portion; the sealingsystem comprises a hydraulic propulsion cylinder, a propulsion piston, afront end cover, a sealing tube, a thickened end portion, and anexpansion rubber tube, the sealing tube sequentially penetrates througha plurality of axes of the front end cover and the propulsion piston, arear end of the sealing tube and the propulsion piston are fixedlyconnected into a whole, the expansion rubber tube and a front end of thesealing tube are butted and coaxially connected, the sealing tube andthe front end cover are dynamically sealed, the propulsion piston andthe hydraulic propulsion cylinder are dynamically sealed, a front end ofthe hydraulic propulsion cylinder is detachably connected to a rear endof the front end cover and sealed, a rear end of the hydraulicpropulsion cylinder is fixedly connected to the middle connecting body,and an oil inlet and outlet port having both ends respectivelycommunicating with the outside and an inner chamber of the hydraulicpropulsion cylinder is also provided in the middle connecting body; andthe injection system comprises a hydraulic valve body and an injectiongun tube, the hydraulic valve body is coaxially mounted inside thehydraulic adjusting tube in the pressure storage system and thehydraulic valve body and the hydraulic adjusting tube are dynamicallysealed at front ends, the injection gun tube is coaxially sleeved insidethe sealing tube and penetrates through the propulsion piston, thethickened end portion is coaxially and detachably connected to a frontend of the injection gun tube, a rear end of the injection gun tube isfixedly connected to the middle connecting body, and a front end of thehydraulic valve body has a cone area fitting a groove at the rear end ofthe injection gun tube.
 2. The hydraulic accumulator-based controllablepressure injection device according to claim 1, wherein the annularpiston is dynamically sealed with the pressure cylinder and thehydraulic adjusting tube through a guide strip and a Glyd ring,respectively, so that the annular piston is slidable between thehydraulic adjusting tube and the pressure cylinder.
 3. The hydraulicaccumulator-based controllable pressure injection device according toclaim 1, wherein the pressure cylinder front half portion and the endportion of the middle connecting body are welded together, the pressurecylinder rear half portion and the rear end cover are connected by aplurality of threads, and a plurality of O rings are providedtherebetween respectively for sealing.
 4. The hydraulicaccumulator-based controllable pressure injection device according toclaim 1, wherein a raised circular ring is provided on an end face ofthe middle connecting body facing the pressure cylinder, the raisedcircular ring being located in an inner chamber of the pressurecylinder.
 5. The hydraulic accumulator-based controllable pressureinjection device according to claim 1, wherein the hydraulic propulsioncylinder is connected to the rear end of the front end cover by aplurality of threads, an O ring is provided therebetween to ensuresealing of a hydraulic oil, and a guide strip and a step seal areprovided between the front end cover and the sealing tube to ensuresealing of the hydraulic oil.
 6. The hydraulic accumulator-basedcontrollable pressure injection device according to claim 1, wherein thethickened end portion is connected to the injection gun tube by aplurality of threads, and the hydraulic valve body and the hydraulicadjusting tube are dynamically sealed through a guide sleeve and a Glydring.
 7. The hydraulic accumulator-based controllable pressure injectiondevice according to claim 1, wherein the groove at the rear end of theinjection gun tube and the cone area at the front end of the hydraulicvalve body are both chamfers of 45 degrees, and the groove is a 1×1 mmchamfer, and the cone area is an 8×8 mm chamfer.
 8. The hydraulicaccumulator-based controllable pressure injection device according toclaim 1, wherein the rear end of the hydraulic propulsion cylinder iswelded to the middle connecting body, and the rear end of the injectiongun tube is fixed to the middle connecting body by welding.
 9. Ahydraulic accumulator-based controllable pressure injection method,comprising the following steps: a, inserting an injection gun tube intoa rock borehole, and pushing, by a propulsion piston, a sealing tube topush an expansion rubber tube to a thickened end portion such that anouter diameter of the injection gun tube is enlarged to fit an innerwall of the rock borehole to form a sealed space at a bottom of the rockborehole; b, starting a hydraulic valve body to fit a groove at a rearend of the injection gun tube, and feeding a high pressure fluid mediumvia a high pressure fluid inlet flow passage to form a high pressurearea in a front section of a pressure cylinder; c, monitoring pressurechanges of the pressure cylinder and an accumulator; and d, after apressure reaches a predetermined value, reducing the pressure in ahydraulic adjusting tube to 0 gradually, when a pressure generated bythe high pressure area against a cone area at a front end of thehydraulic valve body is greater than an oil path pressure in thehydraulic adjusting tube at a rear end, allowing the hydraulic valvebody to slide backwards to be separated from the groove at the rear endof the injection gun tube, and allowing the high pressure fluid mediumto instantaneously surge into the sealed space at the bottom of the rockborehole under own pressure and a thrust of an annular piston, whereinthe pressure generated is sufficient to cause a rock to break from aninside.
 10. The hydraulic accumulator-based controllable pressureinjection method according to claim 9, wherein the high pressure fluidmedium is a high pressure foam or a high pressure water.
 11. Thehydraulic accumulator-based controllable pressure injection deviceaccording to claim 3, wherein the annular piston is dynamically sealedwith the pressure cylinder and the hydraulic adjusting tube through aguide strip and a Glyd ring, respectively, so that the annular piston isslidable between the hydraulic adjusting tube and the pressure cylinder.12. The hydraulic accumulator-based controllable pressure injectiondevice according to claim 4, wherein the annular piston is dynamicallysealed with the pressure cylinder and the hydraulic adjusting tubethrough a guide strip and a Glyd ring, respectively, so that the annularpiston is slidable between the hydraulic adjusting tube and the pressurecylinder.
 13. The hydraulic accumulator-based controllable pressureinjection device according to claim 5, wherein the annular piston isdynamically sealed with the pressure cylinder and the hydraulicadjusting tube through a guide strip and a Glyd ring, respectively, sothat the annular piston is slidable between the hydraulic adjusting tubeand the pressure cylinder.
 14. The hydraulic accumulator-basedcontrollable pressure injection device according to claim 6, wherein theannular piston is dynamically sealed with the pressure cylinder and thehydraulic adjusting tube through a guide strip and a Glyd ring,respectively, so that the annular piston is slidable between thehydraulic adjusting tube and the pressure cylinder.
 15. The hydraulicaccumulator-based controllable pressure injection device according toclaim 7, wherein the annular piston is dynamically sealed with thepressure cylinder and the hydraulic adjusting tube through a guide stripand a Glyd ring, respectively, so that the annular piston is slidablebetween the hydraulic adjusting tube and the pressure cylinder.
 16. Thehydraulic accumulator-based controllable pressure injection deviceaccording to claim 8, wherein the annular piston is dynamically sealedwith the pressure cylinder and the hydraulic adjusting tube through aguide strip and a Glyd ring, respectively, so that the annular piston isslidable between the hydraulic adjusting tube and the pressure cylinder.